Fail dmesg check if it contains Call Trace or segfault

[guoguojenna]

00:00:33 fail /rdma/pyverbs-tests-2 (on default-0) [1/1]
00:00:00 pass dmesg (before-test check)
00:00:02 pass avc (after-test check)
00:00:01 fail dmesg (after-test check)

When users notice dmesg fail, they can go to check the dmesg output to see if it's a bug.

Fixes #2563.

Pull Request Checklist

• implement the feature

[happz]

@guoguojenna thanks for the patch. I for one like the idea, but I'm afraid that the check would have to be smarter to avoid spoiling all tests. Without taking timestamps into account, one segfault - even a segfault that happened right after the boot, way before tmt connected to the guest for the first time - would mark all following tests as failed. I'm afraid dmesg check would have to approach it in the way AVC check does, i.e. checking dmesg output since test's start_time, see https://github.com/teemtee/tmt/blob/main/tmt/checks/avc.py#L137C4-L137C4. I also found https://unix.stackexchange.com/questions/729243/how-to-show-dmesg-logs-within-a-certain-timeframe, but sed is probably not going to help as much as in that example. Maybe we could save /proc/uptime and check only newer lines, and avoid converting into human-readable date & time completely.

[happz]

@guoguojenna thanks for the patch. I for one like the idea, but I'm afraid that the check would have to be smarter to avoid spoiling all tests. Without taking timestamps into account, one segfault - even a segfault that happened right after the boot, way before tmt connected to the guest for the first time - would mark all following tests as failed. I'm afraid dmesg check would have to approach it in the way AVC check does, i.e. checking dmesg output since test's start_time, see https://github.com/teemtee/tmt/blob/main/tmt/checks/avc.py#L137C4-L137C4. I also found https://unix.stackexchange.com/questions/729243/how-to-show-dmesg-logs-within-a-certain-timeframe, but sed is probably not going to help as much as in that example. Maybe we could save /proc/uptime and check only newer lines, and avoid converting into human-readable date & time completely.

Actually, dmesg -c should clean the buffer. Running dmesg -c > some-log.txt before the test should empty the buffer, and running dmesg > another-log.txt after the test would provide the pile of text to check for issues.

[guoguojenna]

Ran the test again after this code change, and can fail the dmesg as expected.

    00:00:37 fail /rdma/pyverbs-tests-2 (on default-0) [1/2]
    00:00:01     pass dmesg (before-test check)
    00:00:02     pass avc (after-test check)
    00:00:02     fail dmesg (after-test check)

[thrix]

@juk @psss @happz this seems to be ready for review

[juk]

@juk @psss @happz this seems to be ready for review

Looks good to me, thank you guoguojenna !

[psss]

Looks good, thanks for implementing this. Proposing to extend the test coverage in 35dd22c.

To be covered in a separate patch.

[psss]

/packit test

[psss]

/packit test -i full